1. Field of the Invention
The present invention relates to a DC-DC converter control circuit, a DC-DC converter, and a DC-DC converter control method. More particularly, the present invention is concerned with a technology capable of maintaining a predetermined relationship of voltages established among a plurality of output voltages of DC-DC converters.
2. Description of the Related Art
In semiconductor circuits, a threshold voltage Vth of a transistor and various resistances vary along with a difference in a manufacturing process, a change in an operational ambient temperature, or a fluctuation of a supply voltage or the like. The operating velocity of a circuit varies depending on the variations. Consequently, the threshold voltage Vth and resistances are actively monitored in order to apply an appropriate supply voltage. Thus, the characteristics of a semiconductor circuit are held optimal all the time.
As related arts, Japanese Unexamined Patent Publications Nos. 2005-166698, H07(1995)-111314, and H07(1995)-176624 have been disclosed.